It looks like in your case they need to update the meeting time for your excursion to better fit the all-ashore time.
Don't forget that you'll meet your group onboard probably before they have the all-ashore time. So if port time is 8:00 am, it isn't unusual to have a meeting time of 7:15 or 7:30. They have to check everyone in, hand out towels and sometimes consent/release forms. Then you'd walk down all together. That usually does kill a good 45 minutes all told.
They list the times of excursions, from the time you meet onboard, to the time you're dropped back at the ship usually.